kernel/linux.git/drivers/net/macvlan.c, branch v6.1.168

macvlan: observe an RCU grace period in macvlan_common_newlink() error path

2026-03-04T12:20:07+00:00

[ Upstream commit e3f000f0dee1bfab52e2e61ca6a3835d9e187e35 ] valis reported that a race condition still happens after my prior patch. macvlan_common_newlink() might have made @dev visible before detecting an error, and its caller will directly call free_netdev(dev). We must respect an RCU period, either in macvlan or the core networking stack. After adding a temporary mdelay(1000) in macvlan_forward_source_one() to open the race window, valis repro was: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source (ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 &) ; sleep 0.5 ; ping -c1 -I p1 1.2.3.4 PING 1.2.3.4 (1.2.3.4): 56 data bytes RTNETLINK answers: Invalid argument BUG: KASAN: slab-use-after-free in macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) Read of size 8 at addr ffff888016bb89c0 by task e/175 CPU: 1 UID: 1000 PID: 175 Comm: e Not tainted 6.19.0-rc8+ #33 NONE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) kasan_report (mm/kasan/report.c:597) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) ? tasklet_init (kernel/softirq.c:983) macvlan_handle_frame (drivers/net/macvlan.c:501) Allocated by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) __kasan_kmalloc (mm/kasan/common.c:419) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5657 mm/slub.c:7140) alloc_netdev_mqs (net/core/dev.c:12012) rtnl_create_link (net/core/rtnetlink.c:3648) rtnl_newlink (net/core/rtnetlink.c:3830 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131) Freed by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) kasan_save_free_info (mm/kasan/generic.c:587) __kasan_slab_free (mm/kasan/common.c:287) kfree (mm/slub.c:6674 mm/slub.c:6882) rtnl_newlink (net/core/rtnetlink.c:3845 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131) Fixes: f8db6475a836 ("macvlan: fix error recovery in macvlan_common_newlink()") Signed-off-by: Eric Dumazet Reported-by: valis Link: https://patch.msgid.link/20260213142557.3059043-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: fix error recovery in macvlan_common_newlink()

2026-02-11T12:37:25+00:00

[ Upstream commit f8db6475a83649689c087a8f52486fcc53e627e9 ] valis provided a nice repro to crash the kernel: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 ping -c1 -I p1 1.2.3.4 He also gave a very detailed analysis: The issue is triggered when a new macvlan link is created with MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan port and register_netdevice() called from macvlan_common_newlink() fails (e.g. because of the invalid link name). In this case macvlan_hash_add_source is called from macvlan_change_sources() / macvlan_common_newlink(): This adds a reference to vlan to the port's vlan_source_hash using macvlan_source_entry. vlan is a pointer to the priv data of the link that is being created. When register_netdevice() fails, the error is returned from macvlan_newlink() to rtnl_newlink_create(): if (ops->newlink) err = ops->newlink(dev, ¶ms, extack); else err = register_netdevice(dev); if (err < 0) { free_netdev(dev); goto out; } and free_netdev() is called, causing a kvfree() on the struct net_device that is still referenced in the source entry attached to the lower device's macvlan port. Now all packets sent on the macvlan port with a matching source mac address will trigger a use-after-free in macvlan_forward_source(). With all that, my fix is to make sure we call macvlan_flush_sources() regardless of @create value whenever "goto destroy_macvlan_port;" path is taken. Many thanks to valis for following up on this issue. Fixes: aa5fd0fb7748 ("driver: macvlan: Destroy new macvlan port if macvlan_common_newlink failed.") Signed-off-by: Eric Dumazet Reported-by: valis Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com Closes: https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u Cc: Boudewijn van der Heide Link: https://patch.msgid.link/20260129204359.632556-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: fix possible UAF in macvlan_forward_source()

2026-02-06T15:43:54+00:00

[ Upstream commit 7470a7a63dc162f07c26dbf960e41ee1e248d80e ] Add RCU protection on (struct macvlan_source_entry)->vlan. Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts. This allows macvlan_forward_source() to skip over entries queued for freeing. Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)). Fixes: 79cf79abce71 ("macvlan: add source mode") Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260108133651.1130486-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

macvlan: Don't propagate promisc change to lower dev in passthru

2023-11-28T17:07:06+00:00

[ Upstream commit 7e1caeace0418381f36b3aa8403dfd82fc57fc53 ] Macvlan device in passthru mode sets its lower device promiscuous mode according to its MACVLAN_FLAG_NOPROMISC flag instead of synchronizing it to its own promiscuity setting. However, macvlan_change_rx_flags() function doesn't check the mode before propagating such changes to the lower device which can cause net_device->promiscuity counter overflow as illustrated by reproduction example [0] and resulting dmesg log [1]. Fix the issue by first verifying the mode in macvlan_change_rx_flags() function before propagating promiscuous mode change to the lower device. [0]: ip link add macvlan1 link enp8s0f0 type macvlan mode passthru ip link set macvlan1 promisc on ip l set dev macvlan1 up ip link set macvlan1 promisc off ip l set dev macvlan1 down ip l set dev macvlan1 up [1]: [ 5156.281724] macvlan1: entered promiscuous mode [ 5156.285467] mlx5_core 0000:08:00.0 enp8s0f0: entered promiscuous mode [ 5156.287639] macvlan1: left promiscuous mode [ 5156.288339] mlx5_core 0000:08:00.0 enp8s0f0: left promiscuous mode [ 5156.290907] mlx5_core 0000:08:00.0 enp8s0f0: entered promiscuous mode [ 5156.317197] mlx5_core 0000:08:00.0 enp8s0f0: promiscuity touches roof, set promiscuity failed. promiscuity feature of device might be broken. Fixes: efdbd2b30caa ("macvlan: Propagate promiscuity setting to lower devices.") Reviewed-by: Gal Pressman Signed-off-by: Vlad Buslov Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20231114175915.1649154-1-vladbu@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: macvlan: Use built-in RCU list checking

2022-11-14T10:50:02+00:00

hlist_for_each_entry_rcu() has built-in RCU and lock checking. Pass cond argument to hlist_for_each_entry_rcu() to silence false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled. Execute as follow: ip link add link eth0 type macvlan mode source macaddr add The rtnl_lock is held when macvlan_hash_lookup_source() or macvlan_fill_info_macaddr() are called in the non-RCU read side section. So, pass lockdep_rtnl_is_held() to silence false lockdep warning. Fixes: 79cf79abce71 ("macvlan: add source mode") Signed-off-by: Chuang Wang Signed-off-by: David S. Miller

net: macvlan: fix memory leaks of macvlan_common_newlink

2022-11-10T14:59:06+00:00

kmemleak reports memory leaks in macvlan_common_newlink, as follows: ip link add link eth0 name .. type macvlan mode source macaddr add kmemleak reports: unreferenced object 0xffff8880109bb140 (size 64): comm "ip", pid 284, jiffies 4294986150 (age 430.108s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 b8 aa 5a 12 80 88 ff ff ..........Z..... 80 1b fa 0d 80 88 ff ff 1e ff ac af c7 c1 6b 6b ..............kk backtrace: [] kmem_cache_alloc_trace+0x1c7/0x300 [] macvlan_hash_add_source+0x45/0xc0 [] macvlan_changelink_sources+0xd7/0x170 [] macvlan_common_newlink+0x38c/0x5a0 [] macvlan_newlink+0xe/0x20 [] __rtnl_newlink+0x7af/0xa50 [] rtnl_newlink+0x48/0x70 ... In the scenario where the macvlan mode is configured as 'source', macvlan_changelink_sources() will be execured to reconfigure list of remote source mac addresses, at the same time, if register_netdevice() return an error, the resource generated by macvlan_changelink_sources() is not cleaned up. Using this patch, in the case of an error, it will execute macvlan_flush_sources() to ensure that the resource is cleaned up. Fixes: aa5fd0fb7748 ("driver: macvlan: Destroy new macvlan port if macvlan_common_newlink failed.") Signed-off-by: Chuang Wang Link: https://lore.kernel.org/r/20221109090735.690500-1-nashuiliang@gmail.com Signed-off-by: Paolo Abeni

net: macvlan: change schedule system_wq to system_unbound_wq

2022-10-14T07:28:19+00:00

For FT2000+/64 devices, when four virtual machines share the same physical network interface, DROP will occur due to the single core CPU performance problem. ip_check_defrag and macvlan_process_broadcast is on the same CPU. When the MACVLAN PORT increases, the CPU usage reaches more than 90%. bc_queue > bc_queue_len_used (default 1000), causing DROP. Signed-off-by: zhangxiangqian Signed-off-by: David S. Miller

macvlan: enforce a consistent minimal mtu

2022-10-09T18:55:05+00:00

macvlan should enforce a minimal mtu of 68, even at link creation. This patch avoids the current behavior (which could lead to crashes in ipv6 stack if the link is brought up) $ ip link add macvlan1 link eno1 mtu 8 type macvlan # This should fail ! $ ip link sh dev macvlan1 5: macvlan1@eno1: mtu 8 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 02:47:6c:24:74:82 brd ff:ff:ff:ff:ff:ff $ ip link set macvlan1 mtu 67 Error: mtu less than device minimum. $ ip link set macvlan1 mtu 68 $ ip link set macvlan1 mtu 8 Error: mtu less than device minimum. Fixes: 91572088e3fd ("net: use core MTU range checking in core net infra") Reported-by: syzbot Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: move from strlcpy with unused retval to strscpy

2022-08-31T21:11:07+00:00

Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang Acked-by: Marc Kleine-Budde # for CAN Link: https://lore.kernel.org/r/20220830201457.7984-1-wsa+renesas@sang-engineering.com Signed-off-by: Jakub Kicinski

vlan: adopt u64_stats_t

2022-06-10T04:53:09+00:00

As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type") we should use u64_stats_t and related accessors to avoid load/store tearing. Add READ_ONCE() when reading rx_errors & tx_dropped. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski